Validation, Verification & Monitoring


"Obtaining evidence that the control measures managed by the HACCP plan and by the operational PRPs are capable of being effective"


"Confirmation, through the provision of objective evidence, that specified requirements have been fulfilled.”


"Conducting a planned sequence of observations or measurements to assess whether control measures are operating as intended”


Cleaning validation is not directly a legal requirement but is seen as food manufacturing best practices. Indeed, audit schemes based on the Global Food Safety initiative (GFSI) such as the British Retail Consortium (BRC) Global Standard for Food Safety Issue 9, provide guidance on the need for validation. Clause 4.11.3 states that: ‘Where cleaning procedures are part of a defined pre-requisite plan to control the risk of a specific hazard, the cleaning and disinfection procedures and frequency shall be validated and records maintained’. In other words, BRC are advocating that validation is required when the cleaning and disinfection programme is intended to control a hazard.

The need for validation is summarised below:

  • Where the cleaning and disinfection programme is designed to control a hazard, it must always be validated.

  • Where the cleaning and disinfection programme is designed to control a brand protection issue, validation is at the discretion of the food manufacturer.

  • Where the cleaning and disinfection programme is designed to control a quality or process control objective, validation is not advocated.

A clean is deemed effective when the desired levels of cleanliness (chemical, physical and microbiological) have been achieved. Testing this can be done through a number of techniques; the choice of test depending on the hazard that is being controlled (microbiological, physical, chemical).


Verification is a series of analytical data, records and observations that provide evidence that cleaning programmes have been carried out according to the validated methods. Traditionally, records have consisted of cleaning programme sign-off sheets by hygiene staff to indicate that cleaning programmes have been undertaken and by production staff to record that the food processing environment was fit for production. Verification may include taking samples to check for microbiological, physical and chemical contamination. These methods may take several days to provide results and thus asks the question, did the cleaning programme work effectively on the day of verification sampling? Alternatively rapid tests may be used as long as the test and its level of sensitivity is sufficient to confirm 'cleanliness'.

Cleaning programmes can be routinely audited to demonstrate that they are being carried out with respect to best practice and written procedures either internally (1st party) as part of an ISO9001 system, via Kersia as the hygiene supplier (2nd party) or via fully independent auditors e.g. BRC (3rd party).


Hygiene Monitoring

Prior to analytical testing of the cleanliness of surfaces, surfaces should first be visually assessed.  This can be via direct observation, smell or the rubbing of the surface with a clean white cloth or gloves to try and determine any physical indications of soiling.  Surfaces that are physically dirty, require no other testing to determine the success of the physical cleaning performance.

Measurement of any residues of food present on surfaces can then be carried out, typically with commercial ATP or protein test kits, and can give quick results during the cleaning process to establish whether a re-clean is required.

For example, ATP testing uses the presence of Adenosine Triphosphate on reaction to create pulses of light that can be read using an instrument. Also, protein or glucose testing and rapid allergen testing can identify any residues on a surface determining whether a re-clean needs to take place.

Allergen Monitoring

Specific tests exist called Lateral Flow Devices which can deliver a presence/absence result in a matter of minutes, ensuring that a surface can be made available for processing in the knowledge that the allergen of concern is not present.

The technology is similar to ELISA in that an antibody – antigen reaction is taking place with a visual indication revealing the presence or absence of the allergenic protein.

Using this technology either a food sample or environmental contact swab can be taken to test for the presence of, for instance: Peanut, Hazelnut, Almond, Casein (Milk), Egg, Gluten, Shellfish & Soya.

It is also possible to use DNA testing to look for allergens and animal species.

Chemical Monitoring

Any cleaning regime requires the selection of the correct detergent and disinfectant strength, with routine checks carried out to ensure that this desired strength has been met.

In-line Monitoring

Most acid or caustic, cleaning in place (CIP), detergents can be monitored in-line by conductivity. The conductivity probe and controller must be calibrated, and temperature compensated, to ensure accuracy; as a rule, each 1°C rise in temperature will increase conductivity by approximately 2%.

With peracetic acid and chlorinated based products redox measurement is generally used because conductivity tends to be unreliable and inaccurate.

Chemical Titration

The strength of detergents or disinfectants should be checked regularly through chemical titration. This can be done either in a QC Laboratory using traditional burettes or by a dropper bottle method, with the chemistry identical in both. A common misconception is that a burette is more accurate than a dropper, but this is largely untrue.

Test Strips

Colour change test strips provide a quick indication on the approximate concentration of certain active components in a detergent or disinfectant; whilst pH paper will deliver a quick indication of any residual acidity or alkalinity following on from a detergent clean. Test strips looking for PAA and QAC can give a good indication as to the strength of the disinfectant.

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